Lost Lake East Reservoir Report

Last Updated: December 4, 2025

Lost Lake East is a vital water resource located in Alpine County, California, serving as a public utility for the surrounding area of Mesa Vista.


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Summary

This earth dam was completed in 1925, standing at a height of 15 feet and with a storage capacity of 230 acre-feet. The dam's primary purpose is water supply, supporting irrigation and other water supply needs in the region.

Managed by the California Department of Water Resources (DWR) under the Safety of Dams program, Lost Lake East is regulated, permitted, inspected, and enforced by the state agency to ensure its safe operation. Despite its low hazard potential and satisfactory condition assessment, the dam undergoes regular inspections to maintain its reliability and safety. The dam stands on Lost Creek, with a drainage area of 0.1 square miles and a surface area of 20 acres.

Lost Lake East not only provides essential water supply but also contributes to the overall climate resilience of the region. With its historical significance dating back to the early 20th century, the dam continues to play a crucial role in water management and environmental conservation efforts in Alpine County. Its location within the San Francisco District and its designation as a public utility underscore its importance in sustaining the local ecosystem and meeting the water needs of the community.

Year Completed

1925

Dam Length

240

Dam Height

15

River Or Stream

Lost Creek

Primary Dam Type

Earth

Surface Area

20

Hydraulic Height

11.4

Drainage Area

0.1

Nid Storage

230

Hazard Potential

Low

Nid Height

15
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.

Hazard Potential Classification

High
Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.